Medical evidence has a "decisive role" to play in criminal cases relating to offences against the human body and experts' opinion should be supported by convincing reasons, the Supreme Court has said.

A bench of Justices P C Ghose and R F Nariman observed this while dismissing an appeal challenging a verdict of the Bombay High Court setting aside the 2010 judgement of a trial court convicting two persons in an alleged murder case.

The apex court said if the report of a medical expert is "slipshod" and cryptic, his opinion is of no value and it also breaks the important links of prosecution evidence.

"In criminal cases pertaining to offences against human body, medical evidence has decisive role to play. A medical witness who performs a post-mortem examination is a witness of fact though he also gives an opinion on certain aspects of the case," the bench said.

"Experts' opinion should be demonstrative and supported by convincing reasons. Court cannot be expected to surrender its own judgement and delegate its authority to a third person, however great," it said.

Dealing with the facts of the case, the bench said the cause of injuries was not stated in the post-mortem report of the deceased and the prosecution failed to prove that death was caused due to injuries inflicted by the recovered weapons.

"Where the medical evidence is such that it does not give any clear opinion with respect to the injuries inflicted on the body of victim or deceased, as the case may be, the possibilities that the injuries might have been caused by the accused are also ruled out," the bench said.

It refused to interfere with the findings of Aurangabad Bench of the Bombay High Court, saying it had rightly acquitted the accused by giving them benefit of doubt.

A trial court at Osmanabad had convicted two persons in the case and had awarded them life imprisonment in 2010.